Dog Digestive System: Guide to Digestion for Healthy Gut
· by Glendon Lloyd Dip.Canine.Nutrition Dip.Dog.Nutrigenomics
Digestive System and Digestion – Key To Dog Health
Summary A dog’s digestive system plays a vital role in its overall health, responsible for breaking down food, absorbing nutrients, and maintaining immune function. While dogs may not digest carbohydrates as efficiently as humans, they are still capable of doing so with the help of enzymes in the small intestine. Plant-based foods rich in prebiotic fibres offer additional benefits by supporting gut health and promoting the growth of beneficial bacteria. This comprehensive guide explores the structure of a dog’s digestive system, common digestive issues, and how to maintain a healthy gut at all life stages.
The canine digestive system is a complex network of organs designed to break down food, absorb nutrients, and eliminate waste. The primary components of this system include:
Mouth: Where food enters and is chewed into smaller pieces. Unlike humans, dogs do not have significant levels of amylase in their saliva to break down carbohydrates in the mouth, but mechanical chewing prepares food for digestion.
Oesophagus: A muscular tube that pushes food from the mouth to the stomach through peristalsis.
Stomach: Food is mixed with gastric juices, breaking down proteins and fats. The dog’s stomach is highly acidic, helping to digest meat and bones efficiently.
Small Intestine: The majority of digestion and nutrient absorption occurs here. Enzymes from the pancreas and bile from the liver assist in the breakdown of proteins, fats, and carbohydrates.
Large Intestine: Water and electrolytes are absorbed, and beneficial bacteria ferment any remaining fibres.
Rectum and Anus: Waste material is expelled from the body as faeces.
Key Functions of the Digestive System
The digestive system in dogs serves three key functions:
Nutrient Absorption: The system breaks down proteins, fats, and carbohydrates into smaller molecules such as amino acids, fatty acids, and glucose, which are absorbed into the bloodstream.
Immune Support: The gut is a critical part of the immune system. Beneficial gut bacteria prevent harmful pathogens from colonising and help maintain immune balance.
Waste Elimination: The digestive system ensures the removal of waste products and toxins through the production and elimination of faeces.
Ingestion: Food is consumed and chewed in the mouth. Though dogs do not have significant amylase in their saliva, chewing breaks food down into smaller particles.
Swallowing and Oesophageal Transport: Food is moved down the oesophagus to the stomach through peristalsis.
Stomach Digestion: In the stomach, strong gastric acids break down proteins and fats. The acidity of the dog’s stomach (around pH 1-2) allows for the efficient digestion of meat and bone.
Small Intestine Digestion and Absorption: Food passes into the small intestine, where enzymes from the pancreas (including amylase, lipase, and protease) further break down proteins, fats, and carbohydrates. The pancreas helps dogs digest carbohydrates, albeit less efficiently than humans.
Nutrient Absorption: Nutrients such as amino acids, fatty acids, and glucose are absorbed through the walls of the small intestine into the bloodstream.
Large Intestine Fermentation and Water Absorption: Beneficial bacteria in the large intestine ferment leftover fibres, producing beneficial compounds. Water and electrolytes are absorbed to form solid waste.
Elimination: Waste material is expelled as faeces through the rectum and anus.
Role of Enzymes and Bacteria
The pancreas secretes digestive enzymes that are essential for breaking down food:
Amylase: Breaks down starches into smaller carbohydrate molecules to aid digestion
Protease: Breaks down proteins into amino acids so the dog’s body can use them
The gut also contains a vast array of beneficial bacteria (the microbiome) that ferment fibres, produce short-chain fatty acids, and support immune function. These bacteria are vital for maintaining a healthy digestive tract.
Are Dog and Human Digestive Systems the Same?
Key Differences Between Canine and Human Digestion
While there are similarities between dog and human digestion, key differences affect how each species processes food:
Stomach Acidity: Dogs have much more acidic stomachs than humans, allowing them to digest raw meat and bones efficiently without the risk of bacterial infection.
Carbohydrate Digestion: Dogs are capable of digesting carbohydrates, though not as efficiently as humans. While humans produce amylase in their saliva to begin carbohydrate digestion in the mouth, dogs rely more on pancreatic enzymes in the small intestine to break down starches and sugars.
Digestive Tract Length: Dogs have a shorter digestive tract than humans, meaning food passes through their system more quickly, typically within 8-10 hours compared to 24-72 hours in humans.
What are Common Dog Digestive Problems and Issues?
Common Digestive Disorders in Dogs
Dogs can suffer from various digestive issues, which may affect their nutrient absorption, energy levels, and overall health. Common digestive disorders include:
Gastroenteritis: Inflammation of the stomach and intestines, often caused by infections, allergies, or dietary indiscretion.
Pancreatitis: Inflammation of the pancreas, which impairs the production of digestive enzymes, leading to improper digestion and nutrient malabsorption.
Food Allergies and Sensitivities: Certain ingredients in a dog’s diet, such as grains (wheat, and corn) or specific proteins, most frequently meat or fish proteins, can trigger allergic reactions, leading to digestive upset and other health issues.
Symptoms of Digestive Problems
Common signs of digestive distress in dogs include:
These symptoms should be evaluated by a veterinarian to determine the underlying cause and provide appropriate treatment.
How Long Do Dogs Take to Digest Food?
Factors Influencing Digestion Time in Dogs
The digestion time in dogs can vary greatly depending on several factors, with a typical range between 8 to 10 hours, though some dogs may digest food within 4 to 12 hours. The specific time depends on a combination of factors, including size, breed, type of food, and health conditions. (1)
Size and Breed: Larger dogs, such as Great Danes or Mastiffs, typically take longer to digest food due to their larger stomach capacity and slower metabolic rates. On average, large breeds may take up to 12 hours to complete the digestive process. Smaller breeds like Chihuahuas and Toy Poodles, with faster metabolisms, may complete digestion in as little as 4 to 6 hours. (2)
Type of Food: The composition of a dog’s meal greatly influences digestion time. Protein-rich, meat-based diets tend to be digested more quickly compared to meals high in fibre or complex carbohydrates. For example, a diet that is predominantly raw meat can be digested in 4 to 6 hours, while a high-fibre, plant-based meal may take up to 10 to 12 hours. Dry kibble, due to its processing and lower moisture content, takes longer to break down, often requiring up to 10 hours for complete digestion.
Health Status: Health issues like pancreatitis, inflammatory bowel disease (IBD), or irritable bowel syndrome (IBS) can significantly slow digestion. In dogs with compromised digestive systems, digestion may take 12 to 24 hours or more. Additionally, stress or anxiety can impact gut motility, causing either slowed digestion or gastrointestinal upset.
Exercise and Activity Levels: A dog’s activity level can influence digestion time. More active dogs tend to have faster metabolisms, which can shorten digestion time to 6 to 8 hours. Sedentary dogs, on the other hand, may experience slower digestion, with times closer to the 10 to 12-hour range.
Hydration: Proper hydration aids digestion by helping to soften food and move it more efficiently through the digestive tract. Dogs that drink plenty of water with their meals are likely to digest food more efficiently, whereas dehydration can slow down the process, adding several hours to the digestion time.
On average, it takes between 8-10 hours for a dog to digest food, but this range can vary depending on individual factors.
Do Dogs’ Digestive Systems Change as They Age?
How Aging Affects Canine Digestion
As dogs age, several changes occur in their digestive system that can impact how efficiently they process and absorb nutrients. These changes often require dietary adjustments to support optimal digestive health in senior dogs.
Reduced Enzyme Production: As dogs grow older, the production of digestive enzymes, particularly amylase (which breaks down carbohydrates), lipase (which breaks down fats), and protease (which breaks down proteins), decreases. This reduced enzyme activity can make it harder for senior dogs to fully digest their food, leading to nutrient malabsorption. For instance, lipase deficiency may result in maldigestion of fats, causing diarrhoea or steatorrhea (fatty stools).
Slower Gut Motility: Aging often leads to a slower gastrointestinal motility, meaning the food moves more slowly through the digestive tract. This can result in constipation or delayed gastric emptying. Slower motility is often caused by a decrease in smooth muscle tone in the intestines, which can affect how quickly food passes through the digestive system. Senior dogs may also experience gastroparesis, a condition where the stomach empties slowly, leading to bloating or discomfort.
Altered Gut Microbiome: The balance of beneficial gut bacteria (microbiota) can shift as dogs age, leading to dysbiosis—an imbalance between harmful and beneficial bacteria. A decline in beneficial bacteria can compromise the immune function of the gut and reduce the efficiency of nutrient absorption. This can make senior dogs more susceptible to gastrointestinal infections, diarrhoea, or weight loss due to poor nutrient uptake.
Decreased Absorption of Nutrients: With age, the small intestine’s ability to absorb nutrients diminishes. Older dogs may have trouble absorbing vitamins and minerals like B vitamins, vitamin E, and calcium, which are critical for maintaining energy levels, immune function, and bone health. Additionally, older dogs may require higher-quality, easily digestible proteins to maintain muscle mass due to reduced protein synthesis.
Dental Health: Many senior dogs experience dental issues such as tooth decay, gum disease, or tooth loss, which can impact their ability to chew food properly. Poor chewing can affect how well food is broken down before it reaches the stomach, leading to incomplete digestion or digestive discomfort.
Increased Sensitivity to Fat: As dogs age, their ability to process dietary fats can decline due to reduced pancreatic function. High-fat meals may lead to gastrointestinal distress, such as diarrhoea, vomiting, or pancreatitis, especially in breeds prone to the condition (e.g., Miniature Schnauzers, Shetland Sheepdogs). Lower-fat diets with easily digestible proteins are often recommended for senior dogs to avoid fat malabsorption.
Metabolic Slowdown: Aging also leads to a slower metabolism, which affects how quickly a dog’s body uses the energy from food. As a result, senior dogs may require fewer calories to maintain a healthy weight, but the nutrient density of their food should be increased to ensure they still receive adequate vitamins, minerals, and protein. For example, high-quality senior dog foods typically contain fewer calories but more concentrated levels of critical nutrients.
Nutritional Needs in Older Dogs
Older dogs may benefit from diets that are easier to digest, with higher-quality proteins and reduced fat content. Adding probiotics, postbiotics and prebiotic fibres to their diet can help maintain gut health by promoting the growth of beneficial bacteria, which becomes more critical as the microbiome changes with age.
What Stages Do Dogs’ Digestive Systems Go Through?
Puppy, Adult, and Senior Dog Digestive Changes
Puppy Stage: Puppies have sensitive digestive systems that are still developing. They require nutrient-dense food that is easy to digest, and their diet should transition from milk to solid food gradually to prevent digestive upset.
Adult Stage: In adulthood, a dog’s digestive system is more robust, capable of processing a variety of foods, including both proteins and carbohydrates. However, a balanced diet that includes adequate prebiotic fibres is essential for maintaining gut health.
Senior Stage: Senior dogs often require dietary adjustments, as their digestive efficiency decreases. Lower-fat diets with easily digestible proteins and added prebiotic fibres and probiotics can help keep their digestive systems functioning properly.
FAQ: Dog Digestive System and Digestion
What is the process of digestion in dogs?
The process of digestion in dogs begins in the mouth, where food is chewed and mixed with saliva, then moves down the oesophagus to the stomach. In the stomach, acids and enzymes break down proteins and fats, and the small intestine absorbs nutrients. Waste is processed in the large intestine and expelled as faeces.
Do dogs have a different digestive system?
Yes, dogs have a different digestive system than humans. Their digestive system is shorter, and they have more acidic stomachs, allowing them to digest proteins and bones more efficiently. They are less efficient at digesting carbohydrates, but they are still capable of processing them with pancreatic enzymes.
How powerful is a dog’s digestive system?
A dog’s digestive system is highly efficient at breaking down proteins and fats. Their stomach acid is powerful enough to digest raw meat and bones, and their intestines absorb essential nutrients to support overall health.
How do I rebalance my dog’s digestive system?
To rebalance a dog’s digestive system, provide a diet rich in easily digestible proteins and prebiotic fibres to support gut bacteria. Probiotic supplements and specialised digestive supplements for dogs can help restore the balance of beneficial bacteria in the gut, while avoiding processed foods and high-fat meals can prevent further digestive upset.
Can dogs eat grains, and are they beneficial for digestion?
While dogs are capable of digesting grains, they do not digest them as efficiently as humans. However, whole grains such as brown rice and oats provide beneficial fibre that supports digestive health and acts as a prebiotic to nourish gut bacteria. If your dog is not allergic to grains, they can be part of a balanced diet in moderate amounts.
What are signs of poor digestion in dogs?
Signs of poor digestion include vomiting, diarrhoea, constipation, excessive gas, bloating, weight loss, and changes in appetite. If these symptoms persist, it may indicate a digestive disorder that requires veterinary attention.
Can stress affect my dog’s digestion?
Yes, stress can negatively impact your dog’s digestive system. Stress and anxiety can lead to conditions like irritable bowel syndrome (IBS), slow gut motility, or even exacerbate existing digestive problems. Dogs under stress may exhibit symptoms like diarrhoea, vomiting, or loss of appetite.
How important is hydration for digestion in dogs?
Hydration is critical for the digestive process. Water helps soften food, aids in the breakdown of nutrients, and facilitates the smooth movement of food through the digestive tract. Dogs that do not drink enough water may experience slower digestion, constipation, or discomfort.
What role do probiotics and prebiotics play in digestion?
Probiotics are live bacteria that help maintain a healthy balance of gut flora, essential for digestion and nutrient absorption. Prebiotics are fibres that feed these beneficial bacteria. Together, they promote a healthy gut microbiome, which supports digestion, boosts immune function, and reduces inflammation.
Can certain dog breeds be more prone to digestive issues?
Yes, certain breeds are more prone to digestive issues. For example, German Shepherds are known to be susceptible to exocrine pancreatic insufficiency (EPI), while Bulldogs and other brachycephalic breeds may suffer from gastric reflux and bloating. Miniature Schnauzers are often predisposed to pancreatitis, which affects fat digestion.
Do food intolerances and allergies affect digestion?
Yes, food intolerances and allergies can lead to significant digestive issues in dogs. Symptoms may include vomiting, diarrhoea, gas, or even skin issues. Common allergens include chicken, beef, soy, dairy, and grains like wheat. Switching to an elimination diet can help identify specific triggers and alleviate symptoms.
Why is my dog eating grass, and is it related to digestion?
Many dogs eat grass occasionally, and it can be related to digestive upset. Some dogs eat grass to induce vomiting when they feel nauseous, while others may do it for fibre. However, if grass eating is frequent and followed by vomiting, it may indicate an underlying digestive issue that needs to be addressed.
What is peristalsis in dogs?
Peristalsis refers to the rhythmic, wave-like contractions of the muscles in a dog’s digestive tract, particularly the oesophagus and intestines. This process moves food through the digestive system, from the moment it is swallowed until waste is eliminated. Peristalsis ensures that food is broken down, mixed with digestive juices, and moved through the intestines for nutrient absorption and waste excretion. Disruptions in peristalsis can lead to digestive problems, such as constipation or gastrointestinal blockages.
What is the acidity of a dog’s stomach?
A dog’s stomach is highly acidic, with a pH typically ranging from 1 to 2 during the process of digestion. This strong acidity is crucial for breaking down proteins, fats, and bones, as well as for killing harmful bacteria that might be ingested with food. However, during fasting (between meals), the gastric juices in a dog’s stomach are around pH 7.3, which is almost neutral. This neutral state prepares the stomach for efficient digestion once food is consumed. In anticipation of food, the stomach quickly responds, and during the process of eating and digestion, the pH drops to a very acidic range of 1 to 2, ensuring that food is properly digested and pathogens are eliminated.
Conclusion
The dog’s digestive system is critical to its overall health, influencing everything from nutrient absorption to immune function. Though dogs may not digest carbohydrates as efficiently as humans, they can still benefit from them, especially when these carbohydrates are paired with prebiotic fibres from plant-based foods. Prebiotics and probiotics play an essential role in maintaining a balanced gut microbiome, which becomes increasingly important as dogs age. By understanding how your dog’s digestive system works and providing the right foods and digestive supplement, you can help ensure that their gut health remains optimal throughout their life.
Bonza Superfoods and Ancient Grains plant-based dog food is specially formulated to support optimal digestion and promote gut health in dogs of all ages. Its carefully selected ingredients, including superfoods, ancient grains, and prebiotic fibres, work together to ensure that dogs maintain a healthy digestive system while benefiting from balanced nutrition. The following key ingredients and nutrients in Bonza play a vital role in supporting digestive health:
Ancient Grains (Quinoa and Oats): These nutrient-dense grains are rich in fibre and easily digestible carbohydrates, offering sustained energy without putting strain on the digestive system. They are gentle on the stomach, making them suitable for dogs with sensitivities or digestive issues. The fibre content helps promote healthy bowel movements and supports overall gut function.
Prebiotic Fibres (Chicory Rootinulin, baobab, MOS and FOS): Prebiotic fibres in Bonza, such as chicory root and fructooligosaccharides (FOS), help nourish beneficial gut bacteria, promoting a balanced microbiome. By feeding these good bacteria, prebiotics support immune health, aid in nutrient absorption, and reduce the risk of digestive upset.
Yucca schidigera: This plant extract helps reduce ammonia levels in the intestines, which can prevent gastrointestinal discomfort and improve stool quality. Yucca schidigera also has anti-inflammatory properties that can soothe the digestive tract, particularly in dogs with sensitive stomachs or those prone to digestive issues.
Beta-Glucans (from Oats and Mushroom): Beta-glucans are known for their immune-boosting and gut-supporting properties. In addition to promoting healthy digestion, they modulate the immune system and enhance gut health by supporting the integrity of the intestinal lining.
Pumpkin and Sweet Potatoes: These ingredients are excellent sources of soluble and insoluble fibres, which help regulate digestion and promote smooth bowel movements. Pumpkin and sweet potatoes also provide antioxidants, such as beta-carotene, that reduce inflammation in the digestive tract.
Omega-3 Fatty Acids (from Algae Oil): Omega-3 fatty acids are critical for reducing inflammation in the digestive system, especially in dogs prone to gastrointestinal disorders. The inclusion of DHA, EPA, and DPA from algae oil helps maintain a healthy gut environment, supports nutrient absorption, and ensures optimal gut function.
Probiotics (Bacillus species): Probiotics Bacillus velezensis, contribute to maintaining a balanced gut microbiome by introducing beneficial bacteria. These probiotics aid in digestion, improve stool consistency, and support overall digestive health, ensuring that your dog efficiently absorbs essential nutrients.
Postbiotic: TruPet™/TruMune™, which supports gut health by promoting immune function and enhancing the integrity of the digestive lining, ensuring optimal digestion and overall well-being.
The combination of these superfoods, ancient grains, prebiotic fibres, and digestive-supporting ingredients makes Bonza Superfoods and Ancient Grains plant-based dog food an excellent choice for promoting healthy digestion. By fostering a balanced gut microbiome, reducing inflammation, and supporting regular bowel movements, Bonza ensures that your dog’s digestive system functions optimally, contributing to overall health and well-being.
About Glendon Lloyd Dip.Canine.Nutrition Dip.Dog.Nutrigenomics
I have had dogs from the day I was born. Much to my Mum's amusement, my Dad bought home Zetta, a beautiful corgi pupp , as his contribution to our new family!
Fast forward to 2018 and Catherine, my wife, and one of our dogs Poppy, were both diagnosed and treated for cancer within months of each other
Diet and its impact on health, cancer particularly, led me down a rabbit hole of discovery.
I consumed information voraciously - on our diets, our dogs' diets and the impact these have not just on health but also the health of our increasingly fragile planet.
I was humbled by the time and expertise given so freely by doctors and vets, canine nutritionists and scientists, academics and agronomists. The more I learned the more I understood there had to be a better way to improve not just our health but also our dogs and the planet's.
The result of my trip down that rabbit hole is Bonza, a plant-based dog food (and now supplements) that elevate our dogs' diet beyond simple nutrition to a diet that inspires a healthier everyday life for our dogs and the planet.
I am continually researching the nutritional impact our dogs' diets have on their health and wellbeing and the ingredients and nutrients we should include in, and exclude from, their food to deliver longer, healthier lives.
I am delighted that my trip down the rabbit hole has led to me completing a Diploma in Canine Nutrigenomics and a Diploma in Canine Nutrition being awarded a Distinction for both my coursework and theses!
Average Customer Rating:
★★★★★
4.9/5
Independent Rating Based on 120 verified reviews. Read all reviews
Join our live interactive community and mailing list to get access to unique perks, info, tips and advice and the ability to connect with other owners who also want the best for their dog!
